Whilst most people using this site will probably be happy to
make a few litres or a bucketful of gunge or slime, there will always be those
that need to make more. This page is therefore aimed at providing information
that may be of use if you want to produce larger quantities (even as far as
filling a swimming pool). Please read the other general gunge pages first to
understand the basic properties & general choices.

Quantities up to 1000-2000 Litres

The
main part of this page is valid up to quantities of around 1000-2000
litres, although this not a hard and fast limit. It will therefore suit
most intermediate users such as those wanting to fill paddling pools,
dunk tanks or ‘slime run’ obstacles. Quantities above this may
favour different techniques, but I have produced approximately
8000 litres successfully using these methods.

Thickener

The first consideration will be which substance to use.
There are two main issues here; Cost and ease of mixing.

Cost

Many
of the possibilities described in the other pages of this website will
not be cheap enough to make a large quantity practical. This leaves two
main possibilities; Guar Gum and Xanthan Gum. At the time of writing,
they are approximately equivalent in price, I would therefore use
whatever you can be obtain at a reasonable cost, but bear in mind
whilst comparing cost per kilo that the grade chosen can affect the
viscosity of the mix.

Ease of Mixing

Many of the options of thickener work best when mixed in hot
water, and in some cases like Natrasol this is essential. Thankfully both Guar
Gum and Xanthan Gum both mix into cold water well.

Gunge proportions

I normally work with proportions of 1.5% thickener, but when
in bulk you may be able to reduce this somewhat. I would postulate that the
proportions used in the iconic game shows ‘Run the Risk’ and ‘Get Your Own Back”
are a lower proportion. The images on this page use 1.5%
thickener.

Colouring

As for smaller quantities, I would recommend using powder
paints as the colourant. I will typically use 3% by weight where the colouring
needs to be strong and when the coverage on people needs to be opaque. The
images on this page use this proportion. If the colouring needs to just work in
bulk, then the quantity can be massively reduced. Bear in mind that at 3%, the
colouring may stain light fabrics, so the choice of concentration would need to
take account of this.

Water

You will need a sufficient water supply directly available
where you are mixing, as well as a power supply. The flow through a domestic
hose can be quite low, so it is worth planning beforehand to make sure you get a
sufficient flow. The speed that the gunge can be made may be related to how fast
you can fill the containers you are using.

Equipment

There are a number of possible ways of mixing the gunge, but
my preferred option up to about 1000 litres is now to use a plaster mixer and a
couple of plastic drums of about 60 litre capacity.

60 litre plastic drum and plaster mixer

It is possible to mix the gunge in bulk, putting the quantity
of water needed into the pool/ tank you are using and stirring the colourant and
thickener. In my experience, producing about 400 litres this way, it is very
difficult to get a thorough mix as you need a powerful mixer to get the full
volume of water circulating quickly enough to get good thorough mixing- indeed I
burnt out an electric drill doing this and ended up with somewhat lumpy gunge.
It is possible to obtain mixers to go into a standard drill, and for smaller
batches these can be effective. The plaster mixer is however more suited to the
larger batches as they are generally more powerful, operate at a suitable speed
and have a slow start- for a one off they can usually be hired.

Process

My preferred production method starts with pre-weighing
ingredients into plastic containers so that they are ready for use. Bear in mind
that these need to be kept dry up until they are used so you may need to cover
them or weigh indoors if there is any chance of rain or splashing. It is also
important to make sure all items coming in contact with the gunge are
clean.

In parallel I will fill the plastic drums using a hose until
they reach about 50 litres. It is useful to have some headspace when mixing, so
50 litres in a 60 litre drum works well. I tend not to use significantly bigger
drums as the 50 litres can be lifted and carried between two people easily.

The plaster mixer is then used to stir the water thoroughly
whilst the colourant and thickener is added.

Weighing out material and mixing

Should you wish to mix larger quantities, larger drums up to
oil drum size (220 litres ish) could be used, but you are likely to need access
to mechanical handling equipment to move these around.

Mixing any large quantity will take some time to do- as
mentioned above the ability to fill containers with water will be key to this,
but so will the time needed on each batch, which cumulatively can become
significant. I often find making the gunge the day before it needs to be used is
a good idea and helps reach the deadline.

I would strongly recommend making trial batches of material
first, before mixing large quantities- you will need to know your choices will
work well for your application.

Pools of gunge made for various eventsInflatable pool contains 500 litres, black tank about 250

Disposal

Consideration needs to be given to the best method of
disposing of the gunge after use. I would avoid directly dumping the thick
material into a sewer to avoid any chance of blockage. The gunge will degrade
after a few days back to water, so if time is available it can then be run to
sewerage safely.

In some cases we have tipped out the material onto grass- the
water is absorbed quickly. The remainder is then primarily colourant of which
the bulk is chalk.

An alternative is to have the gunge collected by a liquid
waste company- this is likely to be the most environmentally sound method, but
also the most expensive.

The resultant goo

Very Large Quantities

Quantities exceeding 1000-2000 litres will almost certainly
need different techniques, although the majority of the factors discussed above
will still be valid. I am aware of very few instances where this sort of
quantity has been used so will discuss these as case histories;

Mythbusters

The Mythbusters produced an episode where they tested the
myth of swimming in treacle vs. water. For this they used guar gum and used a
cement truck to mix. From the footage it is clear the mixing was ineffective as
the material ‘fisheyed’, partially gelled with solid lumps which tends to float
to the surface. I would postulate that mixing in this way is not sufficiently
high shear to be effective.

Nickelodeon Kids Choice Awards

Nickelodeon have produced a number of stunts over the past
few years, some of which have used significant quantities of slime- this has
been commercially supplied by Blair Adhesives, in one case at least shipped in
by tanker. Notable here is that Blair Adhesives will have commercial equipment
designed to mix large quantities in significant batch sizes away from site. This
would seem to be the most effective method to me- elsewhere I am sure contract
manufacturing could be used.

University of Minnesota

In 2005 a team from the University of Minnesota one the
IgNobel prize for their research as to whether it is quicker to swim in syrup or
water. To achieve this they thickened up the water in their university pool with
guar gum, but in very low concentrations, hence the mixing wouldn’t have been as
difficult as would be envisaged.

Recommendations

If
you are looking at an event where very large quantities of gunge are
needed (above about 2000 litres), then I would suggest it warrants
investigating a contract manufacturer to pre-mix it away from site. If
sufficient water supplies are available, a tolerance for a small
quantity of lumps is possible and mechanical handling is available, the
use of tipping skips of 500-100 litre capacity would provide a route to
production on site. Other industrial mixing equipment may prove
possible to use too.

If making the goop in advance, or needing to keep it in use
for some time, then it may be necessary to use preservatives as degradation can
occur in a few days (especially in hot conditions).

It should be noted that any structure needed to contain large
quantities will also need careful consideration and design to withstand all the
forces on it.

Industrial Food or Cosmetic Mixer

Further information

For further sources of information, and on services
superpants.net can offer your event, please see the further info
page.

Photo Credits

Many thanks to those that provided photos for this web page,
copyright of these remains with the photographer (c) 2013;